In a silver halide color photographic material a color image is formed when the element is exposed to light and then subjected to color development. The color development results in imagewise reduction of silver halide and production of oxidized primary amine developer. The oxidized primary amine developing agent subsequently reacts with one or more incorporated dye-forming couplers to form dye in an imagewise fashion.
Photographic materials employing silver halide emulsions with a high chloride content are often readily developable and can lead to dye formation with high efficiency. Silver bromide, silver bromoiodide and other low-chloride emulsions can have superior photographic speed and resistance to fogging but are usually less readily developable. The rate or extent of development of such emulsions can be sensitive to the nature of the couplers incorporated in the photographic material, since the reactivity of the couplers can influence the local concentrations of oxidized developer, which in turn can influence the local reducing power of the developer solution. Many yellow dye-forming couplers that have been used in the art have low reactivity with oxidized developer. This can lead to inefficient dye formation, due to both decreased silver development and due to low efficiencies for scavenging oxidized developer by the coupler.
It would be desirable to have yellow-dye forming couplers that result in higher dye-formation efficiencies, particularly in photographic materials comprising silver bromide emulsions, silver bromoiodide emulsions or other silver halide emulsions with low chloride content. It is at the same time desirable to provide a yellow dye that has acceptable hue and good stability to heat and light.
There are many references to yellow dye-forming couplers in the art. Among them are U.S. Pat. Nos. 3,973,968 of Fujihara et al, 4,022,620 of Okumura et al and 5,066,574 of Kubota et al, which disclose the synthesis and use of yellow dye-forming couplers with hydantoin derivatives as coupling-off groups and Canadian Patent 1,039,291 which discloses yellow dye-forming couplers with oxazolidine-2,4-dione coupling-off groups.
U.S. Pat. No. 5,066,574 of Kubota et al discloses acylacetanilide yellow-dye forming couplers with sulfonate substituents, among many other substituents. International Patent WO 91/08515 of Leyshon et al discloses a sulfonate substituted pivaloylacetanilide coupler (coupler 6), among other couplers, in combination with high-chloride silver halide emulsions and bisphenol compounds. U.S. Pat. No. 4,026,709 of Piller et al discloses specific acylacetanilide yellow dye-forming couplers with sulfonate substituents, among other substituents. European Patent Application 447,969 of Shimura et al discloses a cyclic acylacetanilide yellow dye-forming coupler with a sulfonate substituent. None of these patent publications disclose the use of the particular sulfonate substituted acylacetanilide yellow dye-forming imaging coupler of the invention in a low- or non-chloride silver halide emulsion layer nor do any of them disclose the unexpected advantages associated with such conjoint usage.
It is a problem to be solved to provide a photographic element having a blue-light sensitive layer containing a yellow dye-forming image coupler exhibiting better yellow dye-forming properties than those heretofore known.